What appeared before - the Bubafonya furnace or solid fuel boilers such as the Lithuanian Stropuva, is not exactly known. Another thing is important: both varieties use the principle of top burning, lasting 8-10 hours on 1 tab of firewood. If you need such a length of work, try making the Bubafony stove with your own hands from improvised materials - a gas cylinder, a steel pipe, a barrel. Description and drawing of the heating unit we will provide in this publication.
The device of the upper combustion furnace
The design of this type of heater is very different from traditional wood bourgeois. The “Bubafonya” vertical stove consists of the following elements (see drawing):
- cylinder-shaped firebox with ash door and removable top cover;
- disc cargo with air distributors welded to the end of the air pipe;
- grate;
- chimney connection pipe.
Reference. The simplest version of "Bubafoni" is done without grates at all. But cleaning the stove is extremely inconvenient, you have to disconnect the chimney and turn the case over.
The cylindrical shape of the walls of the combustion chamber is due to 3 reasons:
- From the point of view of aerodynamics, a round pipe is always better than a profile one. Rising along the walls, the combustion products evenly heat the body of the potbelly stove.
- There are no fillet welds - a weak spot in any steel furnace or boiler.
- During burning, the remaining fuel does not “hang” in the corners, which is observed even in some boilers of long burning.
The upper end of the air pipe is equipped with a damper for manual control of the air supply to the furnace. A load of disk form is attached to it from below (other popular names are pancake, piston). Direct or curved air flow distributors are welded from below to the disk. The pipe itself passes through the firebox cover with a minimum clearance of 2–4 mm.
How does the Bubafonya long burning furnace work:
- We fill the chamber to the top with solid fuel - firewood, coal, sawdust. We kindle fuel directly from above, as shown in the photo. Then insert the piston into the furnace, close the lid.
- Open the flap at the end of the duct. When the stove flames up, we cover the air supply by about half.
- Burning occurs in the upper zone of the fuel bookmark, under the pancake. It is there that under the influence of the natural draft of the chimney air comes from the pipe. Distributors contribute to better flow dispersion.
- Hot gases pass through the gap between the disk and the housing, give off heat to the walls of the chamber and rush into the chimney.
- As the wood burns through, the load falls under its own weight until it hits the grate.
An important feature of Bubafoni. Since the combustion of fuel occurs from top to bottom, the combustion zone is gradually shifted after the piston. The walls around the glowing layer of firewood warm up as much as possible (sometimes red-hot), the temperature of the rest of the body is much lower.
Dimensions and parameters of the heater
Since the maximum heating zone is relatively narrow and constantly moves downward, it is quite difficult to calculate the actual capacity of the Bubafony furnace. We suggest not to waste time on calculations, it is better to use data obtained from practical experience:
- for heating a garage or a small utility room with an area of up to 20 m² we make a potbelly stove from a 50-liter gas cylinder with a diameter of 300 mm;
- to heat a room of 20 ... 30 squares, we take a steel pipe Ø400 ... 500 mm or a round iron tank of the same size;
- to heat the greenhouse you will need a stove with a diameter of 50-60 cm (for example, from a 200-liter barrel).
Note.In a large greenhouse, it is better to put 2 small potbelly stoves in opposite corners.
Now about the diameters of the duct and chimney. Above is a drawing of a Bubafoni from a gas cylinder with pipe dimensions: air - DN50 (internal passage 50 mm), smoke - DN100. If you plan to make a stove Ø400 ... 600 mm, increase the diameter of the air duct to DN65 (Ø76 x 3.5 mm), the duct - DN150 (Ø159 x 4 mm).
The minimum clearance between the edge of the disk load and the wall of the furnace should be 1 cm. The dimensions of the remaining parts are indicated in the table:
You should not increase the diameter of the Bubafoni over 60 cm, the unit will come out too bulky and inconvenient to operate. Imagine a furnace from a barrel of 600 mm with a piston of Ø580 mm and an air duct of Ø76 - it turns out to be a rather heavy bandura, which will have to be lifted by hand.
In continuous boilers, the issue is resolved differently. Instead of a hefty pancake, a cross-shaped cargo, shown in the photo, is used. True, another problem arises - sometimes the fuel “hangs”, since the ends of the cargo do not reach the walls.
How to make a bubofon from a balloon
Most often, top burning furnaces are made from old propane vessels with a wall thickness of 3 mm. But there is a problem: the propane-butane mixture is heavier than air and does not want to leave the tank on its own. That is, a small residue of combustible gas is likely to remain in the cylinder, which can flare up when the grinder cuts the metal.
To avoid flash or explosion, the cylinder cover is cut off as follows:
- Lay the metal vessel on the ground, open the valve, then turn it off with a gas wrench.
- Using a hose, fill the cylinder with water to displace propane. Then hammer a wooden chop into the hole.
- Carefully cut the cap along the weld with a grinder. When water leaks from the slot, turn the tank and continue working.
Tip. On old cylinders there are stuck valves that do not want to get out. In such situations, the brass faucet is filed with a hand hacksaw for metal (not a machine with a circle!), Then beaten off with a heavy hammer.
First, mark and cut an opening under the ash pan door in the lower part of the vessel, and a chimney hole on top. The further procedure for making the Bubafony stove with your own hands looks like this:
- Make grates from fittings or corners exactly to the internal size of the firebox. Install the grill inside the cylinder.
- Measuring the height from the grate to the cover, determine the piston stroke. Cut the air pipe to this size plus a margin of 30 cm.
- Fabricate the piston. Make a disk with a hole, weld the air duct and distributors from a steel strip of 40 x 4 mm or a corner of 45 x 45 mm. Install a flapper at the end of the pipe.
- In the center of the removed cover, make a hole Ø60 mm under the air duct, which should enter with a minimum clearance. For convenience, handles can be welded to the lid, and for tightness, a steel strip around the body.
- Make an ashpit door and its frame. Install the locking handle.
- Attach the chimney pipe. You can weld a straight piece of pipe or a 90 ° bend up.
- Insert the load into the firebox, close the lid. "Bubafonya" is ready.
The connection diagram of the furnace to the chimney is standard - we connect a horizontal section and bring it out. Laying the pipeline directly through the roof, as is customary in a bathhouse, is highly undesirable. When burning slowly, condensation may form in the Bubafoni chimney, and it’s inconvenient to clean the vertical pipe.
Making a furnace with a water jacket
Turning an ordinary Bubafon into a solid fuel boiler is a task for a professional welder. The boiler jacket must withstand emergency coolant pressure of at least 2 bar, optimally 3 bar. The joints must be boiled clearly and tightly.
The device stove "Bubafonya" with a water jacket is shown in the drawing.Your goal is to wrap the furnace with 3 mm sheet metal, leaving a water opening with a minimum width of 3 cm. To connect to the heating network, you need to put 2 pipes with an inner diameter of 40 or 50 mm.
Comment. It would seem that the simplest solution suggests itself: to put on the second pipe a cylinder, weld a sheet of iron on top. Why it is difficult to realize: firstly, it is difficult to find a thin-walled pipe Ø350 ... 400 mm, secondly, the boiler will turn out to be heavy, it will warm up for a long time.
We discard the idea of forming a cylinder of sheet metal right away; you cannot bend steel with a thickness of 3 mm without industrial rollers. We offer 4 options for making a water shirt for Bubafoni:
- Use thinner metal - 1.5 ... 2 mm, bend the cylinder manually. The process will be accelerated if the sheet is heated with a gas burner or a torch. Such a boiler will not withstand high pressure, but for working with an open heating system it is quite suitable.
- Take 2 sheet blanks, divide each into 3 equal parts and bend along the lines, maintaining an angle of 60 °. We get 2 halves of the hexagon, which we attach to the firebox and weld together. The problem is to find a bending machine.
- Cut 6 faces separately from the metal, then weld butt at an angle of 60 °. The disadvantage of this method is too many seams.
- Make a rectangular box. In this case, the volume of the boiler tank and the warm-up time will increase significantly.
In the drawing, the water circuit depicts the full height of the firebox. We recommend shortening the shirt slightly to the level of grates. The ash chamber practically does not heat up; it makes no sense to surround it with a coolant. Outside, the boiler tank is necessarily insulated with a non-combustible material - basalt fiber.
Features of a potbelly stove - pros and cons
A good master will calmly make a Bubafonu oven in one day, this is a significant plus. The maximum that you have to buy is a cylinder and pipes for scrap metal. Other advantages of a potbelly stove:
- duration of burning on 1 load of 6 ... 10 hours;
- omnivorous - wood waste, garbage, sawdust, freshly cut branches are laid in the furnace;
- ease of repair, any burnt part is easily changed.
Note. It is better to mix garbage, small waste and coal mixed. To heat with only sawdust, you need to weld a metal heel from the bottom to the diffusers, otherwise the chips will block the path to the air. At clean coal, the furnace works mediocre, requiring forced boost.
Cons of "Bubafoni" is much more unpleasant:
- The stove is poorly regulated. When working on high-quality dry wood, the shutter helps to choose the optimal mode. If heated with garbage and raw wood, the duct must be opened completely.
- The omnivorous potbelly stove is a two-edged sword. From burning low-quality fuel, the chimney is clogged with soot literally per day.
- Without good traction, the stove will smoke into the room. Hence the requirement for the height of the chimney is at least 4 m, counting from the grates, the pipe turns 90 ° - no more than two.
- You can’t throw logs on the go, unless you pour a handful of sawdust through the air channel. So, we are learning how to dose the amount of fuel correctly.
- A potbelly stove from an iron barrel of 200 liters is very bulky and inconvenient in terms of operation. The piston is too large and heavy, the thin metal quickly burns out. Fortunately, the case is not difficult to replace.
What is the danger of “Bubafonya": it is impossible to extinguish a well-heated firebox using a damper. Air seeps through the cracks, the decay of the wood continues. The heater must not be left unattended or act radically - lift the lid and pour a bucket of water. A smoke screen is provided.😊